/Engine/Source/Runtime/SlateCore/Public/Fonts/FontCache.h
Performs text shaping on the given range of the string using the given font info. Returns you the shaped text sequence to use for text rendering viaFSlateDrawElement::MakeShapedText. When using the version which takes a start point and length, the text outside of the given range won't be shaped, but will provide context information to allow the shaping to function correctly. ShapeUnidirectionalText is used when you have text that all reads in the same direction (either LTR or RTL).
FShapedGlyphSequenceRef ShapeUnidirectionalText ( const TCHAR * InText, const int32 InTextStart, const int32 InTextLen, const [FSlateFontInfo](API\Runtime\SlateCore\Fonts\FSlateFontInfo) & InFontInfo, const float InFontScale, const [TextBiDi::ETextDirection](API\Runtime\Core\Internationalization\TextBiDi__ETextDirection) InTextDirection, const ETextShapingMethod InTextShapingMethod ) const